It is generally known that proper weight shift and distribution of weight are important aspects of playing sports such as golf and baseball. For example, a correct golf swing is essential for accurately and forcefully striking the ball. The greatest accuracy and power is achieved when weight is shifted first to the back foot and then to the front foot during the swing. In addition, there has been much attention given to the proper placement of weight with regard to parts of the rear foot. It is generally accepted that muscles of the rear leg and ankle should be utilized so that the weight on the rear foot is kept to the inside. There is a tendency for poor golfers to roll their rear foot to the outside when taking the club back during the backswing. This places weight on the outside of the rear foot which is considered improper weight placement that affects use of the muscles of the legs and hips which in turn adversely affects the power of the swing and hence the distance the golf ball travels. Similarly, it has been observed that children learning to play baseball often move forward away from the pitcher when swinging the bat. This rearward weight shift is undesirable and results in reduced swing accuracy and hitting power.
There are many training devices to help with the problem of improper rear foot weight placement, however these are primarily static wedge-shaped devices which keep the batter's or golfer's rear foot canted inwardly to ensure that too much weight is not transferred to the outside of the rear foot during the backswing. However, it is still possible using these devices for too much weight to be applied to the outside of the rear foot and, in fact, the elevation of the outside edge of the golfer's rear foot by the wedge may tend to increase the weight transferred to the outside edge rather than decrease it. There are also training devices for weight shift on the front foot such as shown in U.S. Pat. No. 5,445,384. This patent discloses a golf training device which includes a hemispherical body adapted to be secured to the shoe sole of the user. The body tends to elevate the front of the foot thereby shifting the weight so much to the heel of the foot. During the backswing and downswing, the body rolls over the ground and magnifies the feeling resulting from shifting of weight of the front foot during the backswing and downswing. While this device may be suitable for training the shifting of weight to the front foot, it has no applicability to rear foot weight distribution.
There are also various training devices for developing optimal stance and batting stride for baseball batters, however these are primarily stance indicators for foot positioning rather than weight distribution. An example of such a training aid for baseball includes U.S. Pat. No. 5,642,880 issued to Wiseman et al. which discloses a mat marked with indicia and a pressure-sensitive area for temporarily indicating the final position of the baseball batter's front foot subsequent to swinging the bat.
There is therefore a need in the art for an athlete's weight placement training aid which alerts the athlete when too much weight is being shifted to the outside of the rear foot during the backswing and which prevents this improper weight transfer. There is also a need for a weight shift training device for baseball to signal the batter when his weight has improperly shifting to the rear during the swing of the bat when hitting the ball.